The present invention relates to apparatus for categorizing and accumulating events, and more particularly to an integrated circuit operable by a programmable look-up table storage device for categorizing and accumulating events.
There is a need for apparatus which can rapidly categorize and accumulate data related to microscopic particles (hereinafter referred to as particles), particularly energetic particles emanating from an energy source. Applications for such apparatus are widespread and include such diverse fields as spectrum analysis, water and air pollution studies, oil refining, bacteriology, pathology, metallurgy, basic medical research and medical diagnosis.
While some applications are accommodated by using laboratory type instrumentation, a great many other applications require instruments which can operate on-line in real time, so that the information gained from the categorizing and accumulating process is accurately recorded for later use.
Each of the various instruments used in the applications identified above has three basic elements in common: a detector, apparatus for categorizing and accumulating events, and output circuitry. The critical element in these instruments, and for which numerous devices have been proposed, is apparatus for categorizing and accumulating events.
As stated above, various devices have been proposed for categorizing and accumulating events wherein the events may be data related to particles. However, the proposed devices suffer from various disadvantages. For example, U.S. Pat. No. 4,488,248 discloses a particle-size distribution analyzer having event categorizing and accumulating apparatus which includes a particle detector adapted to produce signals in response to the size of various particles, a plurality of comparators connected in parallel to the particle detector for producing pulses related to the size of a particle, and a plurality of counters each connected to a comparator for counting the pulses produced by the comparator. Event categorization is performed by use of the comparator circuitry which must use the correct reference value in order to properly categorize the events. The accumulation of the events is performed by the counters.
Another proposed device disclosed by U.S. Pat. No. 4,491,926 provides a particle-size distribution analyzer having event categorizing and accumulating apparatus which includes a detector for generating signals proportional to the size of the detected particle, a threshold circuit adapted to remove noises or fragmental signals from the signals generated by the detector, a gate circuit adapted to decide the passage or non-passage of the detection signal through the threshold circuit, and a counter circuit adapted to count the number of detection signals generated by the gate circuit. The size of the particles is differentiated based on a threshold circuit which must be properly adjusted in order to effectively categorize the events.
As previously stated, the event categorizing and accumulating apparatus disclosed by the patents identified above suffer from various disadvantages, namely, they are slow in speed, they add numerous complicated components to what is a very simple system and they are not easily programmed or modified for use in various event categorizing and accumulating applications.
The present invention solves the above described disadvantages by providing programmable, accurate, fast and uncomplicated apparatus for categorizing and accumulating events.